// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MEDIA_BASE_DEMUXER_STREAM_PROVIDER_H_
#define MEDIA_BASE_DEMUXER_STREAM_PROVIDER_H_

#include "base/macros.h"
#include "media/base/demuxer_stream.h"
#include "media/base/media_export.h"
#include "media/base/media_url_params.h"
#include "url/gurl.h"

namespace media {

// Abstract class that defines how to retrieve "media sources" in DemuxerStream
// form (for most cases) or URL form (for the MediaPlayerRenderer case).
//
// The sub-classes do not stricly provide demuxer streams, but because all
// sub-classes are for the moment Demuxers, this class has not been renamed to
// "MediaProvider". This class would be a good candidate for renaming, if
// ever Pipeline were to support this class directly, instead of the Demuxer
// interface.
// TODO(tguilbert): Rename this class. See crbug.com/658062.
//
// The derived classes must return a non-null value for the getter method
// associated with their type, and return a null/empty value for other getters.
class MEDIA_EXPORT DemuxerStreamProvider {
public:
    enum Type {
        STREAM, // Indicates GetStream() should be used
        URL, // Indicates GetUrl() should be used
    };

    DemuxerStreamProvider();
    virtual ~DemuxerStreamProvider();

    // For Type::STREAM:
    //   Returns the first stream of the given stream type (which is not allowed
    //   to be DemuxerStream::TEXT), or NULL if that type of stream is not
    //   present.
    //   NOTE: Once a DemuxerStream pointer is returned from GetStream it is
    //   guaranteed to stay valid for as long as the Demuxer/DemuxerStreamProvider
    //   is alive. But make no assumption that once GetStream returned a non-null
    //   pointer for some stream type then all subsequent calls will also return
    //   non-null pointer for the same stream type. In MSE Javascript code can
    //   remove SourceBuffer from a MediaSource at any point and this will make
    //   some previously existing streams inaccessible/unavailable.
    // Other types:
    //   Should not be called.
    virtual DemuxerStream* GetStream(DemuxerStream::Type type) = 0;

    // For Type::URL:
    //   Returns the URL parameters of the media to play. Empty URLs are legal,
    //   and should be handled appropriately by the caller.
    // Other types:
    //   Should not be called.
    virtual MediaUrlParams GetMediaUrlParams() const;

    virtual DemuxerStreamProvider::Type GetType() const;

private:
    DISALLOW_COPY_AND_ASSIGN(DemuxerStreamProvider);
};

} // namespace media

#endif // MEDIA_BASE_DEMUXER_STREAM_PROVIDER_H_
